I haven't done anything like that, but it sounds like you have thought it through knowledgeably and well. I assume from your post, btw, that your version of the VT100 has a 16 ohm tap, as the photos and schematic here show only 4 and 8 ohm taps.
The one question mark in my mind about doing that would be what would happen if while music is playing a failure were to occur somewhere in the signal path in one of the two paralleled channels, resulting in that channel attempting to output zero volts while the other channel is attempting to output a full amplitude signal. As with many ARC amps the output impedance of the VT100 is not all that high for a tube amp (at the ARC DB page I linked to above it states "output regulation: approximately 0.8dB 8 ohm load to open circuit"), and I would have some concern about the possibility of damage in that situation.
In any event, good luck, and welcome to Audiogon! Regards,
-- Al
The one question mark in my mind about doing that would be what would happen if while music is playing a failure were to occur somewhere in the signal path in one of the two paralleled channels, resulting in that channel attempting to output zero volts while the other channel is attempting to output a full amplitude signal. As with many ARC amps the output impedance of the VT100 is not all that high for a tube amp (at the ARC DB page I linked to above it states "output regulation: approximately 0.8dB 8 ohm load to open circuit"), and I would have some concern about the possibility of damage in that situation.
In any event, good luck, and welcome to Audiogon! Regards,
-- Al